#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 2e5 + 5;

ll gcd(ll a, ll b, ll& x, ll& y) {
  if (b == 0) {
    x = 1, y = 0;
    return a;
  }
  ll d = gcd(b, a % b, y, x);
  y -= a / b * x;
  return d;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  ll a, b;
  cin >> a >> b;
  ll x, y;
  gcd(a, b, x, y);
  x %= b;
  if (x < 0) x += b;
  cout << x;
  return 0;
}